I need some information of some etch mask other than silicon dioxide for KOH
etching.I am doing a long duration etching(atleast 5 hrs)and using a thick
thermally grown oxide mask.But, the sides of my wafer start etching out.I have
tried PECVD Nitride as mask but that does not help.Is there any resist i can
apply to the edges of my wafer during the last 1-1.5hrs of my etching
Manjula